The present invention relates to a device for recycling powder dry chemicals used in fire extinguishers.
Portable fire extinguishers having a limited capability for putting out fires has found extensive use in recent years. Efficient use of fire extinguishers on fires in their early stages has proved successful in preventing loss of lives and property. Underwriters' Laboratories classifies the basic types of fires encountered. Class A fires are those which consume ordinary combustible material such as paper, wood, and the like. Water or water solutions are quite effective in quenching such a fire. Class B fires are those that involve flammable liquids and greases. A blanketing or smoothering type extinguisher material is required to fight this type of fire. Class C fires are those that occur in live electrical equipment. It is essential that an electrically nonconductive extinguishing agent be employed therefore.
For many years the soda-acid type extinguisher was used to fight Class A fires. The chemical reaction between the soda and sulfuric acid generated gasses which expelled a stream of water. However, such extinguishers were found to be ultimately dangerous in that explosions occurred causing great injury to the user thereof. Originally the dry-chemical extinguishers were usable on Class B and Class C fires. Newer dry-chemical extinguishers employ chemicals that may be used on Class A, B, and C fires and have greatly replaced the old soda-acid type extinguishers which have been outlawed in many jurisdictions.
Dry-chemical fire extinguishers must be recharged periodically. This may be due to the fact that they have been discharged or that the pressurizing inert gas, such as air or nitrogen, has escaped from the fire extinguisher. To recharge such dry-chemical extinguishers, removal of the dry-chemical remaining in the fire extinguisher is required before refilling the fire extinguisher with dry-chemical, recycled or new (make-up). It is required in many places that the amount of dry-chemical used in recharging a fire extinguisher be weighed and that the dry-chemical be visually inspected. Most dry-chemicals used in present day fire extinguishers are quite expensive. In addition, exposure to the same creates a medical hazard. Moreover, the dry-chemical found in powder form behaves erratically when handled. For example, many powdered chemicals lump if not constantly agitated.
Prior method of recycling dry-chemical included releasing the pressure from the fire extinguisher without discharging the dry-chemical, manually shaking the fire extinguisher thus dislodging the dry-chemical and directing the same into a bucket, and pouring the dry-chemical back into the fire extinguisher after visual inspection and weighing. The prior method is time consuming and exposes the operator to the noxious particulate dry-chemical.
A device to recycle dry-chemical quickly and safely is needed.